print-null.c revision 172686 
1/*
2 * Copyright (c) 1991, 1993, 1994, 1995, 1996, 1997
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that: (1) source code distributions
7 * retain the above copyright notice and this paragraph in its entirety, (2)
8 * distributions including binary code include the above copyright notice and
9 * this paragraph in its entirety in the documentation or other materials
10 * provided with the distribution, and (3) all advertising materials mentioning
11 * features or use of this software display the following acknowledgement:
12 * ``This product includes software developed by the University of California,
13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
14 * the University nor the names of its contributors may be used to endorse
15 * or promote products derived from this software without specific prior
16 * written permission.
17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
20 *
21 * $FreeBSD: head/contrib/tcpdump/print-null.c 172686 2007-10-16 02:31:48Z mlaier $
22 */
23
24#ifndef lint
25static const char rcsid[] _U_ =
26    "@(#) $Header: /tcpdump/master/tcpdump/print-null.c,v 1.53.2.4 2007/02/26 13:31:33 hannes Exp $ (LBL)";
27#endif
28
29#ifdef HAVE_CONFIG_H
30#include "config.h"
31#endif
32
33#include <tcpdump-stdinc.h>
34
35#include <pcap.h>
36#include <stdio.h>
37#include <string.h>
38
39#include "interface.h"
40#include "addrtoname.h"
41#include "af.h"
42
43#include "ip.h"
44#ifdef INET6
45#include "ip6.h"
46#endif
47
48/*
49 * The DLT_NULL packet header is 4 bytes long. It contains a host-byte-order
50 * 32-bit integer that specifies the family, e.g. AF_INET.
51 *
52 * Note here that "host" refers to the host on which the packets were
53 * captured; that isn't necessarily *this* host.
54 *
55 * The OpenBSD DLT_LOOP packet header is the same, except that the integer
56 * is in network byte order.
57 */
58#define	NULL_HDRLEN 4
59
60
61/*
62 * Byte-swap a 32-bit number.
63 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
64 * big-endian platforms.)
65 */
66#define	SWAPLONG(y) \
67((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
68
69static inline void
70null_hdr_print(u_int family, u_int length)
71{
72	if (!qflag) {
73		(void)printf("AF %s (%u)",
74			tok2str(bsd_af_values,"Unknown",family),family);
75	} else {
76		(void)printf("%s",
77			tok2str(bsd_af_values,"Unknown AF %u",family));
78	}
79
80	(void)printf(", length %u: ", length);
81}
82
83/*
84 * This is the top level routine of the printer.  'p' points
85 * to the ether header of the packet, 'h->ts' is the timestamp,
86 * 'h->len' is the length of the packet off the wire, and 'h->caplen'
87 * is the number of bytes actually captured.
88 */
89u_int
90null_if_print(const struct pcap_pkthdr *h, const u_char *p)
91{
92	u_int length = h->len;
93	u_int caplen = h->caplen;
94	u_int family;
95
96	if (caplen < NULL_HDRLEN) {
97		printf("[|null]");
98		return (NULL_HDRLEN);
99	}
100
101	memcpy((char *)&family, (char *)p, sizeof(family));
102
103	/*
104	 * This isn't necessarily in our host byte order; if this is
105	 * a DLT_LOOP capture, it's in network byte order, and if
106	 * this is a DLT_NULL capture from a machine with the opposite
107	 * byte-order, it's in the opposite byte order from ours.
108	 *
109	 * If the upper 16 bits aren't all zero, assume it's byte-swapped.
110	 */
111	if ((family & 0xFFFF0000) != 0)
112		family = SWAPLONG(family);
113
114	if (eflag)
115		null_hdr_print(family, length);
116
117	length -= NULL_HDRLEN;
118	caplen -= NULL_HDRLEN;
119	p += NULL_HDRLEN;
120
121	switch (family) {
122
123	case BSD_AFNUM_INET:
124		ip_print(gndo, p, length);
125		break;
126
127#ifdef INET6
128	case BSD_AFNUM_INET6_BSD:
129	case BSD_AFNUM_INET6_FREEBSD:
130	case BSD_AFNUM_INET6_DARWIN:
131		ip6_print(p, length);
132		break;
133#endif
134
135	case BSD_AFNUM_ISO:
136		isoclns_print(p, length, caplen);
137		break;
138
139	case BSD_AFNUM_APPLETALK:
140		atalk_print(p, length);
141		break;
142
143	case BSD_AFNUM_IPX:
144		ipx_print(p, length);
145		break;
146
147	default:
148		/* unknown AF_ value */
149		if (!eflag)
150			null_hdr_print(family, length + NULL_HDRLEN);
151		if (!suppress_default_print)
152			default_print(p, caplen);
153	}
154
155	return (NULL_HDRLEN);
156}
157
158/*
159 * Local Variables:
160 * c-style: whitesmith
161 * c-basic-offset: 8
162 * End:
163 */
164